I found this article by Robert Rector on the The Heritage Foundation web site. It is part of their Poverty and Marriage project.

Excerpt:

The Census data presented so far demonstrate that married couples have dramatically lower poverty rates than single parents. These substantial differences in poverty remain even when married couples are compared to single parents of the same race and level of education. The pattern is almost exactly the same in all 50 states.

However, in the Census comparisons, the married couples and single parents are obviously different (albeit similar) persons. It is therefore possible that much of the difference in poverty between married families and single-parent families might be due to hidden differences between married and single parents as individuals rather than to marriage per se. For example, it is possible that unmarried fathers might have substantially lower earnings than married fathers with the same racial and educational backgrounds. If this were the case, then marriage, for these men, would have a reduced anti-poverty effect.

Fortunately, we have other direct data on poverty and unmarried parents that corroborate the Census analysis. These data are provided by the Fragile Families and Child Well-being Survey conducted jointly by Princeton and Columbia universities.[16] The Fragile Families survey is a representative national sample of parents at the time of a child’s birth, with a heavy emphasis on lower-income unmarried couples. The survey is unusual in collecting information not only on single mothers, but on non-married fathers as well, including (critically) the actual employment and earnings of the father in the year prior to birth.

Because the Fragile Families Survey reports both the mothers’ and fathers’ earnings, it is simple to calculate the poverty rate if the non-married mothers remain single and if each unmarried mother married her child’s father (thereby pooling both parents’ income into a joint family income). The Fragile Families data show that if unmarried mothers remain single, over half (56 percent) of them will be poor. (This high level of poverty will persist for years: Half of all unwed mothers will be poor five years after the child is born.[17]) By contrast, if the single mothers married the actual biological fathers of their children, only 18 percent would remain poor.[18] Thus, marriage would reduce the expected poverty rate of the children by two-thirds.

It is important to note that these results are based on the actual earnings of the biological fathers of the children and not on assumed or hypothetical earnings. Moreover, the non-married fathers in the sample are relatively young. Over time, their earnings will increase and the poverty rate for the married couples will decline farther.

[…]Census data and the Fragile Families survey show that marriage can be extremely effective in reducing child poverty. But the positive effects of married fathers are not limited to income alone. Children raised by married parents have substantially better life outcomes compared to similar children raised in single-parent homes.

When compared to children in intact married homes, children raised by single parents are more likely to have emotional and behavioral problems; be physically abused; smoke, drink, and use drugs; be aggressive; engage in violent, delinquent, and criminal behavior; have poor school performance; be expelled from school; and drop out of high school.[19] Many of these negative outcomes are associated with the higher poverty rates of single mothers. In many cases, however, the improvements in child well-being that are associated with marriage persist even after adjusting for differences in family income. This indicates that the father brings more to his home than just a paycheck.

The effect of married fathers on child outcomes can be quite pronounced. For example, examination of families with the same race and same parental education shows that, when compared to intact married families, children from single-parent homes are:

• More than twice as likely to be arrested for a juvenile crime;[20]
• Twice as likely to be treated for emotional and behavioral problems;[21]
• Roughly twice as likely to be suspended or expelled from school;[22] and
• A third more likely to drop out before completing high school.[23]

The effects of being raised in a single-parent home continue into adulthood. Comparing families of the same race and similar incomes, children from broken and single-parent homes are three times more likely to end up in jail by the time they reach age 30 than are children raised in intact married families. [24] Compared to girls raised in similar married families, girls from single-parent homes are more than twice as likely to have a child without being married, thereby repeating the negative cycle for another generation.[25]

Finally, the decline of marriage generates poverty in future generations. Children living in single-parent homes are 50 percent more likely to experience poverty as adults when compared to children from intact married homes. This intergenerational poverty effect persists even after adjusting for the original differences in family income and poverty during childhood.[26]

You should definitely click through the article and view all the colorful charts and diagrams. This article should be printed out and used to explain the connection between fiscal conservatism and social conservatism.

I also want to point out that two notable groups on the left act to destroy marriage. First of all, there are the feminists, who oppose the unequal gender roles in marriage. They lobby for feminist policies that destroy marriage, like no-fault divorce. Second, there are the socialists, who favor redistribution of wealth from productive to non-productive people. They lobby for increased welfare for single mothers, causing more single-mother households. Either way, marriage is under attack by the left. I have not even mentioned things like sex education and state-run day care.

What should the government do?

I think that government does have a role in providing financial incentives in the form of tax breaks to married couples who have children and stay married. The government should give bigger and bigger tax breaks as marriages last longer and longer, and have more children. And the biggest tax breaks of all should be given to families where one parent stays at home while the children are not yet in school, during the crucial early years. Sounds crazy, doesn’t it? But if research agrees that marriage is good for children, good for married couples, and good for society, then why aren’t we doing more to inform people about the benefits of marriage, and providing them with financial incentives to marry for the long-term?